clk: msm: clock-pll: Add support for sleep enabled pll

Add new clock ops to be used by sleep enabled plls. It will clear the
sleep enable bit for the pll on getting enabled and assert the sleep
enable bit on getting disabled.

Change-Id: I3b8a9a184403e8f72d8f764d487d64b43bf3bfd1
Signed-off-by: Jaydeep Sen <jsen@codeaurora.org>